I'he Tt»tubB lone district sent ex* hibil* from over a hundred of Its mints, Including the Old Guard Grand Central, Emerald. Stonewall and Tougbnui. Mr. Mazon t*sU* malts ihe average yield of speci* mens from the Tombstone district M tW) per too, mill lest A specimen from the Bronco mine will assay into the thousands while one from American mine, lately sold for $100,* 000, assays $15,000 per ton. The horn silver in this specimen is spread on the rock as we spread butter on bread -